1. Field of the Invention
The field of the invention relates to embolic composition delivery devices, and, more particularly, delivery devices for delivering fluid components of an embolic composition.
2. Background of the Invention
In many clinical situations, blood vessels are occluded for a variety of purposes, such as to control bleeding, to prevent blood supply to tumors, or to a diseased blood vessel, such as an arteriovenous malformation (AVM), an arteriovenous fistula, or an aneurysm.
Embolization of blood vessels is particular useful in treating aneurysms. Aneurysms are abnormal blood filled dilations of a blood vessel wall, which may rupture causing significant bleeding. For the cases of intracranial aneurysms, the significant bleeding may lead to damage to surrounding brain tissue or death. Intracranial aneurysms may be difficult to treat when they are formed in remote cerebral blood vessels, which are very difficult to access. If left untreated, hemodynamic forces of normal pulsatile blood flow can rupture fragile tissue in the area of the aneurysm causing a stroke.
Traditionally, intracranial aneurysms have been surgically clipped to reduce the risk of rupture by placing a metal clip around the neck of the aneurysm to cut off and prevent further blood flow to the aneurysm. However, many aneurysms cannot be treated surgically because of either the location and configuration of the aneurysm or because the condition of the patient does not permit cranial surgery.
In another type of treatment, coils are implanted in the body of a patient in an attempt to occlude blood flow to the aneurysm. However, this procedure is time consuming because it often requires bi-plane X-rays after placement of each coil. In addition, the proper size for the coils normally needs to be determined and selected prior to implantation. Also, coils may compact over time, leaving cavities for subsequent growth of the aneurysm.
When the neck of an aneurysm is large, the foregoing methods of treatment of the aneurysm become more difficult, because the neck may have a shape that cannot be completely clipped and the coils may tend to become dislodged from the aneurysm. One aneurysm treatment procedure addressing the problems associated with surgical clipping and coil techniques involves the endovascular injection of a liquid embolic composition that solidifies in and occludes the aneurysm. The liquid embolic composition may include two liquid components that are delivered from separate sources to the aneurysm. Upon contact with each other, the liquid components react and solidify into an embolic mass, thereby occluding the aneurysm. Examples of liquid embolic compositions are described in U.S. Pat. Nos. 6,139,520 and 6,152,943, the entireties of which are expressly incorporated herein by reference. U.S. Pat. No. 6,139,520 discloses a cross linked polysaccharide fiber formed by combining a first liquid including polysaccharide and a second liquid including an ionic cross linking agent. U.S. Pat. No. 6,152,943 discloses a polymer formed by two components.
The delivery of liquid embolic composition to intracranial spaces requires the use of catheters that are relatively soft and flexible in order to navigate to the desired locations. Existing liquid embolic delivery systems that require delivery of more than one liquid component to the distal portion of the delivery catheter may be cumbersome and may have limited utility due to the need to have more than one independent lumen. In addition, delivery systems may be expensive to develop and manufacture due to the need to fabricate multiple components that are specifically required for the systems. Furthermore, when more than one liquid component is delivered to an aneurysm, there is a risk that the liquid components may not be completely combined within the aneurysm to form the desired embolic composition. As the result, the unmixed portion of either one of the liquid components may dissipate into the blood stream or travel to other locations within the body.
In light of the foregoing, it would be advantageous to have improved devices and methods for delivering and combining fluid components of an embolic composition.